/******************************************************************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_text_label.h"
#include "qwt_text.h"
#include "qwt_painter.h"
#include "qwt_math.h"

#include <qstyle.h>
#include <qstyleoption.h>
#include <qpainter.h>
#include <qevent.h>
#include <qmargins.h>

class QwtTextLabel::PrivateData
{
public:
    PrivateData() : indent(4), margin(0)
    {
    }

    int indent;
    int margin;
    QwtText text;
};

/*!
   Constructs an empty label.
   \param parent Parent widget
 */
QwtTextLabel::QwtTextLabel(QWidget* parent) : QFrame(parent)
{
    init();
}

/*!
   Constructs a label that displays the text, text
   \param parent Parent widget
   \param text Text
 */
QwtTextLabel::QwtTextLabel(const QwtText& text, QWidget* parent) : QFrame(parent)
{
    init();
    m_data->text = text;
}

//! Destructor
QwtTextLabel::~QwtTextLabel()
{
    delete m_data;
}

void QwtTextLabel::init()
{
    m_data = new PrivateData();
    setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
}

/*!
   Interface for the designer plugin - does the same as setText()
   \sa plainText()
 */
void QwtTextLabel::setPlainText(const QString& text)
{
    setText(QwtText(text));
}

/*!
   Interface for the designer plugin

   \return Text as plain text
   \sa setPlainText(), text()
 */
QString QwtTextLabel::plainText() const
{
    return m_data->text.text();
}

/*!
   Change the label's text, keeping all other QwtText attributes
   \param text New text
   \param textFormat Format of text

   \sa QwtText
 */
void QwtTextLabel::setText(const QString& text, QwtText::TextFormat textFormat)
{
    m_data->text.setText(text, textFormat);

    update();
    updateGeometry();
}

/*!
   Change the label's text
   \param text New text
 */
void QwtTextLabel::setText(const QwtText& text)
{
    m_data->text = text;

    update();
    updateGeometry();
}

//! Return the text
const QwtText& QwtTextLabel::text() const
{
    return m_data->text;
}

//! Clear the text and all QwtText attributes
void QwtTextLabel::clear()
{
    m_data->text = QwtText();

    update();
    updateGeometry();
}

//! Return label's text indent in pixels
int QwtTextLabel::indent() const
{
    return m_data->indent;
}

/*!
   Set label's text indent in pixels
   \param indent Indentation in pixels
 */
void QwtTextLabel::setIndent(int indent)
{
    if (indent < 0)
        indent = 0;

    m_data->indent = indent;

    update();
    updateGeometry();
}

//! Return label's text margin in pixels
int QwtTextLabel::margin() const
{
    return m_data->margin;
}

/*!
   Set label's margin in pixels
   \param margin Margin in pixels
 */
void QwtTextLabel::setMargin(int margin)
{
    m_data->margin = margin;

    update();
    updateGeometry();
}

//! Return a size hint
QSize QwtTextLabel::sizeHint() const
{
    return minimumSizeHint();
}

//! Return a minimum size hint
QSize QwtTextLabel::minimumSizeHint() const
{
    QSizeF sz = m_data->text.textSize(font());

    const QMargins m = contentsMargins();

    int mw = m.left() + m.right() + 2 * m_data->margin;
    int mh = m.top() + m.bottom() + 2 * m_data->margin;

    int indent = m_data->indent;
    if (indent <= 0)
        indent = defaultIndent();

    if (indent > 0) {
        const int align = m_data->text.renderFlags();
        if (align & Qt::AlignLeft || align & Qt::AlignRight)
            mw += m_data->indent;
        else if (align & Qt::AlignTop || align & Qt::AlignBottom)
            mh += m_data->indent;
    }

    sz += QSizeF(mw, mh);

    return QSize(qwtCeil(sz.width()), qwtCeil(sz.height()));
}

/*!
   \param width Width
   \return Preferred height for this widget, given the width.
 */
int QwtTextLabel::heightForWidth(int width) const
{
    const int renderFlags = m_data->text.renderFlags();

    int indent = m_data->indent;
    if (indent <= 0)
        indent = defaultIndent();

    const QMargins m = contentsMargins();

    width -= m.left() + m.right() - 2 * m_data->margin;
    if (renderFlags & Qt::AlignLeft || renderFlags & Qt::AlignRight)
        width -= indent;

    int height = qwtCeil(m_data->text.heightForWidth(width, font()));
    if ((renderFlags & Qt::AlignTop) || (renderFlags & Qt::AlignBottom))
        height += indent;

    height += m.top() + m.bottom() + 2 * m_data->margin;

    return height;
}

/*!
   Qt paint event
   \param event Paint event
 */
void QwtTextLabel::paintEvent(QPaintEvent* event)
{
    QPainter painter(this);
    painter.setClipRegion(event->region());

    QStyleOption opt;
    opt.initFrom(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this);

    if (!contentsRect().contains(event->rect())) {
        painter.setClipRegion(event->region() & frameRect());
        drawFrame(&painter);
    }

    painter.setClipRegion(event->region() & contentsRect());

    drawContents(&painter);
}

//! Redraw the text and focus indicator
void QwtTextLabel::drawContents(QPainter* painter)
{
    const QRect r = textRect();
    if (r.isEmpty())
        return;

    painter->setFont(font());
    painter->setPen(palette().color(QPalette::Active, QPalette::Text));

    drawText(painter, QRectF(r));

    if (hasFocus()) {
        const int m = 2;

        QRect focusRect = contentsRect().adjusted(m, m, -m + 1, -m + 1);

        QwtPainter::drawFocusRect(painter, this, focusRect);
    }
}

//! Redraw the text
void QwtTextLabel::drawText(QPainter* painter, const QRectF& textRect)
{
    m_data->text.draw(painter, textRect);
}

/*!
   Calculate geometry for the text in widget coordinates
   \return Geometry for the text
 */
QRect QwtTextLabel::textRect() const
{
    QRect r = contentsRect();

    if (!r.isEmpty() && m_data->margin > 0) {
        const int m = m_data->margin;
        r.adjust(m, m, -m, -m);
    }

    if (!r.isEmpty()) {
        int indent = m_data->indent;
        if (indent <= 0)
            indent = defaultIndent();

        if (indent > 0) {
            const int renderFlags = m_data->text.renderFlags();

            if (renderFlags & Qt::AlignLeft) {
                r.setX(r.x() + indent);
            } else if (renderFlags & Qt::AlignRight) {
                r.setWidth(r.width() - indent);
            } else if (renderFlags & Qt::AlignTop) {
                r.setY(r.y() + indent);
            } else if (renderFlags & Qt::AlignBottom) {
                r.setHeight(r.height() - indent);
            }
        }
    }

    return r;
}

int QwtTextLabel::defaultIndent() const
{
    if (frameWidth() <= 0)
        return 0;

    QFont fnt;
    if (m_data->text.testPaintAttribute(QwtText::PaintUsingTextFont))
        fnt = m_data->text.font();
    else
        fnt = font();

    return QwtPainter::horizontalAdvance(QFontMetrics(fnt), 'x') / 2;
}
